Controlling transmission control protocol data

ABSTRACT

A method an apparatus for sending data to a User Equipment via a Radio Access Network node using the Transmission Control Protocol. A TCP node that sends TCP User Plane data to the UE receives a message originating from the RAN node. The message includes a congestion avoidance inhibitor relating to the UE. If the TCP node subsequently detects packet loss is detected between the TCP node and the UE, and the congestion avoidance inhibitor is present, then the TCP node will inhibit a congestion avoidance mechanism. This ensures that congestion avoidance mechanisms, which reduce transmission rate, are not initiated for temporary RAN events such as handover when there is no congestion in the network.

TECHNICAL FIELD

The present disclosure relates to the field of controlling TransmissionControl Protocol data

BACKGROUND

The Transmission Control Protocol (TCP) is a protocol for transmittingdata between points in a communication network. A key feature of TCP isits reliability, as it includes delivery validation mechanisms and errorchecking. TCP is typically used by Web browser applications forconnecting with servers.

A TCP connection is established end-to end. For example, it may beestablished to send data from a TCP server to a client device. In thiscase, the TCP server will typically measure the Round Trip Time (RTT)for sending data to the client, and uses that information to establishan optimal transmission rate. Other factors may influence thetransmission rate, such as the transmission window. The transmissionwindow is a measure of how many packets can be outstanding withoutreceiving an acknowledgement that they have been received.

As shown in FIG. 1, in order to address long RTTs, a TCP proxy can beintroduced. This breaks the TCP connections into two legs, whichshortens the RTT. In FIG. 1, a User Equipment (UE) 1 connects via aRadio Access Network (RAN) node to a network. In this example, the RANnode is an eNodeB (eNB) 2. TCP data is sent via a Serving Gateway (SGW)3 and a Packet Data Network Gateway (PGW) 4 from a TCP proxy 5. One ofthe TCP connection legs is therefore between the TCP proxy 5 and the UE1

The TCP proxy 5 also connects with as TCP server located in a servicenetwork or in the Internet 6. The other TCP connection leg is thereforebetween the TCP proxy 5 and the TCP server.

A feature of TCP is that it includes a congestion avoidance mechanism.Different types of congestion avoidance mechanisms can be used, but theyessentially rely on reducing the transmission rate of data in the eventthat congestion is detected. This means that if congestion isexperienced in part of the network, leading to packet loss orunacceptably long RTTs, then the transmission rate is reduced. This hasthe effect of reducing the congestion in the network and, in most cases,allowing the transmission rate to be gradually increased once more.

During congestion avoidance, the end-user's Quality of Experience (QoE)is reduced, because the transmission rate of data is reduced. It istherefore desirable to avoid having to use a congestion avoidancemechanism unless necessary.

SUMMARY

When a handover of a UE 1 from one Radio Access Network node to anotheris required, as shown in FIG. 1 where a handover of the UE 1 from oneeNB 2 to a further eNB 7 is shown, some packet loss may occur. Effortshave been made to reduce packet loss on handover. For example, in a LongTerm Evolution (LTE) network, a source eNB 2 forwards received packetsto a target eNB 7 on an X2 connection between the eNBs. However, thisdoes not work in every case. For example, a packet destined for the UE 1might be in flight towards source eNB 2, but since buffers are empty inthe source eNB 2, the switch to the new (target) eNB 7 is executed. Asimilar problem may occur for packets (such as acknowledgements) sent onthe uplink from the UE towards a TCP proxy or server. Similar problemsoccur for handover using different Radio Access Technologies (RAT).

It has been realised that when data is sent using a TCP connection, theTCP congestion avoidance mechanisms are initiated on detection of packetloss regardless of the cause of the packet loss. This means thatcongestion avoidance mechanisms are initiated whether packet loss iscaused by congestion or handover. In the case of congestion, theninitiating a congestion avoidance mechanism is appropriate in order totake account of the congestion. However, in the case where packet lossis caused by mobility events such as handover, initiation of acongestion control mechanism may not be necessary but simply reduce theuser's QoE.

According to a first aspect, there is provided a method of sending datato a User Equipment (UE) via a Radio Access Network (RAN) node using theTransmission Control Protocol (TCP). A TCP node that sends TCP userplane data to the UE receives a message originating from the RAN node.The message includes a congestion avoidance inhibitor relating to theUE. If the TCP node subsequently detects packet loss is detected betweenthe TCP node and the UE, and the congestion avoidance inhibitor ispresent, then the TCP node will inhibit a congestion avoidancemechanism.

An advantage of this is that congestion avoidance mechanisms are notinitiated when packet loss is due to a temporary event in the RAN suchas a handover. The TCP node can therefore retransmit the lost packets,but does not reduce the transmission rate. This ensures that the RANevent does not have a negative impact on the users' Quality ofExperience.

An optional example of a TCP node is a TCP proxy.

As described above, an optional example of an event is handover, and inthis case the congestion avoidance inhibitor is received as a result ofthe UE being involved in a handover to a further RAN node.

The congestion avoidance inhibitor is optionally received using adedicated connection. Alternatively, the congestion avoidance inhibitoris optionally included in User Plane data sent between the RAN node andthe TCP node. As a further alternative, the congestion avoidanceinhibitor is included in a packet header.

The TCP node is optionally located between the RAN node (2) and aNetwork Translation Function.

The TCP node optionally subsequently deletes the congestion avoidanceinhibitor. An advantage of this is that congestion avoidance can bestarted again in the event that subsequent packet loss occurs that isrelated to congestion, and not to a temporary event in the RAN such ashandover. As a further option, the congestion avoidance inhibitor isdeleted after the expiry of a predetermined time, or after receiving amessage instructing the TCP node to delete the congestion controlinhibitor. This message may come from any suitable node, such as atarget RAN node once handover is complete.

According to a second aspect, there is provided a method of controllinga flow of TCP data from a TCP node to a UE via a RAN node. A RAN nodedetermines that a handover of the UE to a further RAN node is required.As a result, it sends a message towards the TCP node. The messageincludes a congestion avoidance inhibitor, the congestion avoidanceinhibitor instructing the TCP node to inhibit a congestion avoidancemechanism in the event hat packet loss is detected. An advantage of thisis that the RAN node can inform the TCP node when a temporary event suchas handover may lead to packet loss for reasons other than congestion inthe network, and so the TCP node need not initiate a congestionavoidance mechanism if it detects packet loss. This ensures that theuser's Quality of Experience is not reduced in the event that handoveroccurs.

As an option, the TCP node is a TCP proxy.

The congestion avoidance inhibitor is optionally sent by any of using adedicated connection, including the congestion avoidance inhibitor inUser Plane data sent between the RAN node and the TCP node, or includingthe congestion avoidance inhibitor in a packet header.

As an option, the message includes a time value indicating a time afterwhich the TCP node must delete the congestion avoidance inhibitor.

According to a third aspect, there is provided a TCP node for sendingdata to a UE via a RAN node using the TCP. The TCP node is provided witha transmitter arranged to send TCP User Plane data to the UE. A receiveris provided for receiving a message originating from the RAN node, themessage including a congestion avoidance inhibitor relating to the UE. Amemory is provided for storing the congestion avoidance inhibitor. Aprocessor is also provided, which is arranged to detect packet lossbetween the TCP node and the UE. The processor is further arranged todetermine the presence of the congestion avoidance inhibitor in thememory and, as a result, inhibit a congestion avoidance mechanism.

An optional example of a TCP node is a TCP proxy.

The receiver is optionally arranged to receive the congestion avoidanceinhibitor using any of a dedicated connection, a congestion avoidanceinhibitor included in User Plane data sent between the RAN node and theTCP node, or a congestion avoidance inhibitor included in an existingpacket header.

According to a fourth aspect, there is provided a RAN node for use in acommunication network. The RAN node is provided with a processor fordetermining that a handover of a UE currently attached to the RAN nodeto a further RAN node is required. A transmitter is also provided, whichis arranged to send towards a TCP node a message. The message includes acongestion avoidance inhibitor, the congestion avoidance inhibitorinstructing the TCP node to inhibit a congestion avoidance mechanism inthe event that packet loss is detected between the UE and the TCP node.

As an option, the transmitter is arranged to send the congestionavoidance inhibitor by using any of a dedicated connection, includingthe congestion avoidance inhibitor in User Plane data sent between theRAN node and the TCP node, and including the congestion avoidanceinhibitor in an existing packet header.

An optional example of a RAN node is an eNodeB.

According to a fifth aspect, there is provided a computer programcomprising computer readable code which, when run on a TCP node causesthe TCP node to perform the method as described above in the firstaspect.

According to a sixth aspect, there is provided a computer programcomprising computer readable code which, when run on an RAN node, causesthe RAN node to perform the method as described above in the secondaspect.

According to a seventh aspect, there is provided a computer programproduct comprising a non-transitory computer readable medium and acomputer program as described above in either of the fifth or sixthaspects, wherein the computer program is stored on the non-transitorycomputer readable medium.

According to an eighth aspect, there is provided a vessel or vehiclecomprising any of a TCP node described in the third aspect or a RAN nodedescribed in the fourth aspect

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates schematically in a block diagram a knowncommunication network;

FIG. 2 is a flow diagram illustrating exemplary steps;

FIG. 3 illustrates schematically in a block diagram an exemplarycommunication network and signal flow;

FIG. 4 is a signalling diagram showing an exemplary procedure for a UEhandover;

FIG. 5 illustrates schematically in a block diagram an exemplary TCPnode;

FIG. 6 illustrates schematically in a block diagram an exemplary RadioAccess Network node; and

FIG. 7 illustrates schematically in a block diagram an exemplary vesselor vehicle.

DETAILED DESCRIPTION

Whenever packet loss is detected, existing TCP mechanisms will typicallyinitiate a congestion avoidance mechanism (assuming the amount of packetloss is sufficiently high). However, as described above, in some casesit may not be appropriate to initiate a congestion avoidance mechanism.For example, packet loss may be caused by a mobility event such ashandover of a UE from one RAN node to another. Other temporary issues inthe RAN may give rise to packet loss, but it may not be necessary toimplement a congestion avoidance mechanism.

In order to address this, a RAN node informs the TCP node that it shouldnot initiate a congestion avoidance mechanism. This is achieved by theRAN node sending a message containing a congestion avoidance inhibitortowards the TCP node. FIG. 2 is a flow diagram illustrating exemplarysteps using the type of network shown in FIG. 1. The following numberingcorresponds to that of FIG. 2:

S1. The UE 1 establishes a TCP connection via a first eNB 2 with a TCPproxy 5. Note that this is by way of example, and the UE 1 may in somecircumstances have a direct connection with the TCP server located inthe service network 6. However, in a typical scenario, a TCP proxy 5 isused. Note also that an eNB is used as an example of a RAN node, and anyother suitable RAN node in a different RAT may be used, Note that thesame problem may occur in Wireless Local Area Networks (WLAN) having anAccess Point (AP) that a UE can attach to. Packet loss may occur when aUE moves from one AP to another. The terms RAT and RAN should thereforebe construed as including WLAN as well as other types of access network.

S2. The eNB 2 determines that the UE 1 must perform a handover to afurther eNB 7.

S3. The first eNB 2 is aware that the UE 1 is about to handover to thefurther eNB 7, and so it sends a congestion control inhibitor towardsthe TCP proxy 5.

S4. The TCP proxy 5 receives and stores the congestion controlinhibitor. The congestion control inhibitor is associated with the UE 1.

S5. The TCP proxy 5 subsequently detects packet loss.

S6. Under normal circumstances, the TCP proxy 5 would initiate acongestion avoidance mechanism in the event that packet loss isdetected. However, it determines whether a congestion avoidanceinhibitor is associated with the UE 1 for which packet loss has beendetected.

S7. In the event that a congestion avoidance inhibitor is associatedwith the UE 1 for which packet loss has been detected, the TCP proxy 5does not initiate a congestion avoidance mechanism.

S8. In the event that no congestion avoidance inhibitor is associatedwith the UE 1 for which packet loss has been detected, the TCP proxy 5initiates a congestion avoidance mechanism, as the packet loss is mostlikely due to congestion at some point in the network.

Note that at some point after the temporary RAN conditions are over, thecongestion avoidance inhibitor may no longer be required. For example,once handover from the source eNB 2 to the target eNB 7 is complete,then further packet loss is likely to be due to congestion. In this caseit would be appropriate for the TCP proxy 5 to initiate a congestionavoidance mechanism in the event that packet loss is detected. There arevarious ways that this can be address. A first example is to give thecongestion avoidance inhibitor a lifetime, so that after it has beenstored for a pre-determined period of time, it is deleted from the TCPproxy 5. The predetermined time should be selected according to how longthe handover is expected to take. A second example is for the target eNB7 to send a second message to the TCP proxy 5 once handover is complete,the second message instructing the TCP proxy 5 to delete the congestionavoidance inhibitor. A further example is for a Service Aware node(described below) to instruct the TCP proxy 5 to delete the congestionavoidance inhibitor.

There are various mechanisms by which the TCP proxy 5 can be sent acongestion avoidance inhibitor and instructions to delete the congestionavoidance inhibitor. FIG. 3 shows an exemplary network in which aService Aware (SA) node 8 is used to send signalling between RAN nodesand nodes in the service network 6. An SA node 8 may, for example,inform a service node such as a TCP server of conditions in the RAN,allowing the TCP server to adjust the quality of the media that is beingsent. Similarly, it might inform a node in the RAN of the type of amountof data it can expect to receive from the service node, allowing the RANnode to reserve resources. Note that in the example of FIG. 3, the SAnode 8 and the TCP proxy 5 may be located at the same physical node.

FIG. 4 is a signalling diagram showing exemplary signalling when the UE1 is subjected to a handover from one eNB 2 to a further eNB 7. In thisexample, signalling from the eNBs 2, 7 is sent to the SA node 8. AMobility Management Entity (MME) and a Gateway (GW) 10 are also shown,but if the signalling is sent on the user plane then these entities willnot be involved. In some circumstances, some signalling may be sent viathe GW 10. The following numbering corresponds to that of FIG. 4:

S9. The UE attaches to the eNB 2.

S10. User Plane data traffic is sent from the TCP proxy 5 to the UE 1via the eNB 2 using TCP.

S11. A handover of the UE 1 from the eNB 2 to a further eNB 7 isinitiated.

S12. An event indication is sent from the eNB 2 towards the SA node 8.This informs the SA node that a handover is taking place.

S13. The SA node 8 sends a congestion avoidance inhibitor to the TCPproxy 5. The TCP proxy 5 stores the congestion avoidance inhibitor. Notethat the congestion avoidance inhibitor may include a lifetime duringwhich it will be active at the TCP proxy 5.

S14. At the same time as step S12, handover of the UE 1 from the eNB 2to the further eNB 7 occurs, and the UE attaches to the further eNB 7.Once the handover to the further eNB 7 has occurred, the congestionavoidance inhibitor can be deleted at the TCP proxy 5. As describedherein, there are various mechanisms to ensure that the congestionavoidance inhibitor is not deleted until handover is complete.

S15. User Plane data traffic is sent from the TCP proxy 5 to the UE 1via the further eNB 7 using TCP.

S16. In the event that packet loss is detected, the TCP proxy 5determines the presence of the congestion avoidance inhibitor associatedwith the UE 1 and retransmits lost packets, but does not initiate acongestion avoidance mechanism.

As described above, the congestion avoidance inhibitor may have apredetermined lifetime, or the further eNB 7 may instruct the TCP proxy5 via the SA node 8 to delete the congestion avoidance inhibitorassociated with the UE 1.

Note that while FIGS. 3 and 4 show communication between the eNB 2 andthe TCP proxy 5 via the SA node 8, the communication of the congestionavoidance inhibitor may be sent directly from the eNB 2 to the TCP proxy5.

There are various signalling techniques that can be used to send thecongestion avoidance inhibitor from the eNB 2.

In a first example, a new protocol is provided between the RAN and theTCP proxy 5 using a dedicated outband signalling connection.

In a second example, a new protocol is provided between the RAN and theTCP proxy 5. The congestion avoidance inhibitor is inserted on theactual user plane flow.

In a third example, a new protocol is provided that uses existing unusedflags and bits in the IP and TCP headers, for example using the IPoptions in the IP header.

In a typical mobile network, the operator will provide a Network AddressTranslation (NAT) function on the borders between the mobile network andthe Internet to be able to reuse IP addresses. This leads tocomplications if the TCP server is located outside the NAT function,because the UE IP address is changed to the NAT's IP address for thepayload. There is therefore no common identifier for the UE 1 andsession between the RAN and the TCP server. The only option to signalbetween the RAN and the TCP server in this scenario is to modify theuser payload according to the third example above, by using IP optionsin the IP header, or some flags in the TCP header. This solution mayrequire additional changes, such as recalculation of packet checksumsand so on.

In the event that a NAT function is not used, or if the TCP server isbetween a NAT and the UE 1, or if IP version 6 is used, then the secondexample can be used. In other words, the congestion avoidance inhibitoris transported inband by inserting packets on the user plane path.Alternatively, this protocol could be transported outband on dedicatedsignalling paths. Note that in most circumstances, a TCP proxy 5 will bebetween a NAT and the UE 1

The above description refers to eNBs 2, 7 and a TCP proxy 5. It will beappreciated that any RAN node can be used to signal the congestionavoidance inhibitor, and that the TCP proxy may alternatively be a TCPserver where no TCP proxy is used.

FIG. 5 illustrates schematically in a block diagram a TCP node such asthe TCP proxy 5 discussed above. Note that the node could alternativelybe a TCP server where no TCP proxy is used. In this example, the node isreferred to as a TCP proxy 5. The TCP proxy 5 is provided with atransmitter 11 for sending TCP User Plane data to the UE 1. A receiver12 is provided, for receiving a message originating from the RAN node(the eNB 2 in the examples above). The message includes a congestionavoidance inhibitor relating to the UE. A non-transitory computerreadable medium in the form of a memory is provided for storing thecongestion avoidance inhibitor 14. A processor 15 is also provided. Theprocessor 15 is arranged to detect packet loss between the TCP proxy 5and the UE 1. If packet loss is detected, the processor 15 is arrangedto determine the presence of the congestion avoidance inhibitor in thememory 13 and, as a result, inhibit a TCP congestion avoidancemechanism.

Note that the memory 13 may also be used to store a computer program 16which, when executed by the processor 15, causes the TCP proxy 5 tobehave as described above. Note also that the computer program may beprovided on an external non-transitory computer readable medium 17, suchas a Compact Disk or a flash drive.

FIG. 6 illustrates schematically in a block diagram a RAN node such asthe eNB 2 discussed above. While the invention may be implemented usingany type of RAT, the following description uses an example where the RANnode is the eNB 2. The eNB 2 is provided with a processor 18 fordetermining that handover of the UE is required. A transmitter 19 isalso provided for sending a message towards the TCP proxy 5. The messageincludes a congestion avoidance inhibitor, which instructs the TCP proxy5 to inhibit a congestion avoidance mechanism in the event that packetloss is detected between the UE 1 and the TCP proxy 5.

A non-transitory computer readable medium in the form of a memory 20 isalso provided. The memory 20 may be used to store a computer programwhich, when executed by the processor 18, causes the eNB 2 to behave asdescribed above. Note also that the computer program may be provided onan external non-transitory computer readable medium 22, such as aCompact Disk or a flash drive.

Turning now to FIG. 7, there is illustrated a vessel or vehicle 23, suchas a ship, a train, a car, an aeroplane, a truck and so on. The vesselor vehicle 23 is provided with any of a TCP node 5 as described aboveand a RAN node 2 as described above.

The techniques and apparatus described above improve a user's QoEbecause a congestion avoidance mechanism is inhibited in the event thatthe TCP server or TCP proxy is provided with a congestion avoidanceinhibitor. This is used where a temporary issue in the RAN, such as amobility event, could lead to packet loss, but this packet loss does notrequire a congestion avoidance mechanism to reduce the transmissionrate. The TCP node therefore re-transmits any lost packets but, if thecongestion avoidance inhibitor is present and associated with the UE,does not initiate a congestion avoidance mechanism. This ensures that auser's QoE is not negatively affected by events such as handover.

The skilled person will appreciate that various modifications may bemade to the above described embodiments without departing from the scopeof the present invention as defined in the appended claims. For example,while the invention is described in the context of an LTE network usingeNBs, it will be appreciated that the same techniques could be used inan access network that uses any type of RAT. Similarly, it will beappreciated that the techniques described above can be used to inhibitcongestion avoidance mechanisms from either a TCP proxy or a TCP server.

The following abbreviations have been used in the above description:

AP Access Point

eNB eNodeB

GW Gateway

LTE Long Term Evolution

MME Mobility Management Entity

NAT Network Address Translation

PGW Packet Data Network Gateway

QoE Quality of Experience

RAN Radio Access Network

RAT Radio Access Technologies

RTT Round Trip Time

SA Service Aware

SGW Serving Gateway

TCP Transmission Control Protocol

UE User Equipment

WLAN Wireless Local Area Networks ( ) having an

1. A method of sending data to a User Equipment via a Radio AccessNetwork node using the Transmission Control Protocol, TCP, the methodcomprising: at a TCP node sending TCP User Plane data to the UserEquipment, receiving a message originating from the Radio Access Networknode, the message including a congestion avoidance inhibitor relating tothe User Equipment; and in the event that packet loss is detectedbetween the TCP node and the User Equipment, determining the presence ofthe congestion avoidance inhibitor and, as a result, inhibit operationof a congestion avoidance mechanism.
 2. The method according to claim 1,wherein the TCP node is a TCP proxy.
 3. The method according to claim 1,wherein the congestion avoidance inhibitor is received as a result ofthe User Equipment being involved in a handover to a further RadioAccess Network node.
 4. The method according to claim 1, wherein thecongestion avoidance inhibitor is received by any of: using a dedicatedconnection; including the congestion avoidance inhibitor in User Planedata sent between the Radio Access Network node and the TCP node; andincluding the congestion avoidance inhibitor in a packet header.
 5. Themethod according to claim 1, wherein the TCP node is located between theRadio Access Network node and a Network Translation Function.
 6. Themethod according to claim 5, further comprising, at the TCP node,subsequently deleting the congestion avoidance inhibitor.
 7. The methodaccording to claim 6, wherein the congestion avoidance inhibitor isdeleted after any of the expiry of a predetermined time, and receiving amessage instructing the TCP node to delete the congestion controlinhibitor.
 8. A method of controlling a flow of Transmission ControlProtocol, TCP, data from a TCP node to a User Equipment via a RadioAccess Network node, the method comprising, at the Radio Access Networknode: determining that a handover of the User Equipment to a furtherRadio Access Network node is required; the method characterize bysending towards the TCP node a message, the message including acongestion avoidance inhibitor, the congestion avoidance inhibitorinstructing the TCP node to inhibit operation of a congestion avoidancemechanism in the event that packet loss is detected.
 9. The methodaccording to claim 8, wherein the congestion avoidance inhibitor is sentby any of: using a dedicated connection; including the congestionavoidance inhibitor in User Plane data sent between the Radio AccessNetwork node and the TCP node; and including the congestion avoidanceinhibitor in a packet header.
 10. The method according to claim 8,wherein the message includes a time value indicating a time after whichthe TCP node must delete the congestion avoidance inhibitor.
 11. ATransmission Control Protocol, TCP, node for sending data to a UserEquipment via a Radio Access Network node using the TCP, the TCP nodecomprising: a transmitter arranged to send TCP User Plane data to theUser Equipment, the TCP node comprising: a receiver arranged to receivea message originating from the Radio Access Network node, the messageincluding a congestion avoidance inhibitor relating to the UserEquipment; a memory arranged to store the congestion avoidanceinhibitor; a processor arranged to detect packet loss between the TCPnode and the User Equipment, the processor being further arranged todetermine the presence of the congestion avoidance inhibitor in thememory and, as a result, inhibit operation of a congestion avoidancemechanism.
 12. The TCP node according to claim 11, wherein the TCP nodeis a TCP proxy.
 13. The TCP node according to claim 11, wherein thereceiver is arranged to receive the congestion avoidance inhibitor usingany of a dedicated connection, a congestion avoidance inhibitor includedin User Plane data sent between the Radio Access Network node and theTCP node, and a congestion avoidance inhibitor included in an packetheader.
 14. A Radio Access Network node for use in a communicationnetwork, the Radio Access Network node comprising: a processor fordetermining that a handover of a User Equipment currently attached tothe Radio Access Network node to a further Radio Access Network node isrequired; the Radio Access Network node comprising: a transmitterarranged to send towards a TCP node a message, the message including acongestion avoidance inhibitor, the congestion avoidance inhibitorinstructing the TCP node to inhibit operation of a congestion avoidancemechanism in the event that packet loss is detected between the UserEquipment and the TCP node.
 15. The Radio Access Network node accordingto claim 14, wherein the transmitter is arranged to send the congestionavoidance inhibitor by using any of a dedicated connection, includingthe congestion avoidance inhibitor in User Plane data sent between theRadio Access Network node and the TCP node, and including the congestionavoidance inhibitor in an packet header.
 16. A computer programcomprising computer readable code which, when run on a TCP node causesthe TCP node to perform the method as claimed in claim
 1. 17. A computerprogram comprising computer readable code on a non-transitory computerreadable medium, the computer readable code, when run on an Radio AccessNetwork node, causes the Radio Access Network node to perform the methodas claimed in claim
 8. 18. (canceled)